I had always heard Anselm's argument for the existance of God in a way that was unconvincing. Then I actually read what Anselm wrote. He makes a better case than I imagined, and is actually quite enjoyable to read, but in his proof he uses some sentence-long hyphenated strings of words that are rather difficult to follow. So here, I've reworked Anselm's argument (from his book Proslogion) as a dialog between Andy and his friend Tim, who are, as we walk in, sipping latte's at Starbucks.

"Okay, let's take a different approach," Andy said, after he and Tim had talked for an hour or so about whether God exists. "What," he asked, "is the greatest thing you can imagine?"

"The universe. The universe is all there is."

"Tim, I'm not asking what you believe is the greatest thing. I'm asking what you can imagine is the greatest thing."

"Okay, okay. I know where you are going with this. A god who created everything and knows everything and is the source of everything and never had any beginning and all that stuff is the greatest thing I can imagine. But - and this is a big 'but' buddy - just because I can imagine it doesn't mean it exists. There are lots of things I can imagine that don't exist."

"True, there are lots of things we can imagine that don't exist, but imagining giraffes with elephant noses doesn't involve us in a logical contradiction."

"What logical contradiction?"

"Well, you said the greatest thing you could imagine is this all-powerful, eternal being. And then you said that it only exists in your imagination, right?"

"Yeah. So?"

"Because if this thing - if God - only exists in your head, then it isn't the greatest thing you can imagine. If God also exists in reality, that is far greater than just existing in your mind."

"Hmm. Very clever, Andy. So, the only way to escape the contradiction is to say that the greatest thing exists not only as an idea, but also in reality. Well, I don't know, Andy, I'm going to have to think about that one."